504 PROCEEDINGS OF THE ACADEMY OF 



Caudal fin completely homocercal or equally developed above and below the 

 axial line. 



Pectoral fins variable, with the base concave and descending forwards below. 



Ventral fins jugular, normally developed (I. 5) or with only three articula- 

 ted rays, and a rudimentary spine in each. 



10 + x 



The vertebrae are present in increased number ( ). 



14 + 3/ 



The stomach is siphonal, and the pyloric caeca are obsolete. 



This family is closely related to that of the Uranoscopoids, but appears to 

 be sufficiently distinguished on account of its elongated form, the course of 

 the lateral line, the development of the dorsal and anal fins, and the absence 

 of pyloric caeca. Other characters of less importance, but possessed by all 

 the representatives of the Leptoscopoids, and by none of the Uranoscopoids, 

 are the entire nudity or smoothness of the head, the fringes of the opercula, 

 and the larger size of the scales. 



Its affinities with other families are remote ; the one most nearly allied to 

 it after the Uranoscopoids is that of the Trachinoids. Its relations to the 

 Blennioids are no more intimate than with a number of others. 



The representative of the family of Leptoscopoids may be distributed among 

 three minor groups or subfamilies, as follows : 



I. Pectoral rays branched. Ventral fins perfect, (I. 5). (Dor- 



sal fin remote from nape. Pseudobranchiae developed), Leptoscopin^. 



a. Vomerine and palatine teeth developed Leptoscopus. 



/?. Vomerine and palatine teeth obsolete Crapatalus. 



II. Pectoral rays simply articulated. Ventral fins imperfect, 



each with three simply articulated rays, (I. 3). 



A. Dorsal fiu commencing quite far behind the nape. 



Pseudobranchiae developed Myxodagnim^. 



/?. Head conoid. Lower jaw obtusely pointed and 



with a short flap in front Myxodagnus. 



a.. Head cuboid. Lower jaw transversely rounded 



in front Dactylagnus. 



B. Dorsal fin commencing at the nape. Pseudobranchise 



obsolete Dactyloscopin^;. 



Head cuboid Dactyloscopus. 



In deference to the opinions of some naturalists, I had at one time almost 

 resolved to refer the tridigitate Leptoscopoids to a peculiar family which 

 would be characterized by the simply articulated rays of the pectoral fins and 

 the imperfect blennioid condition of the ventral fins. On reconsideration, 

 however, I am yet unable to convince myself of the propriety of such an act, 

 and think that it will be advisable to at least defer it until the value of family 

 characters among fishes may be better known. 



LEPTOS COPING Gill. 



Leptoscopinse Gill, Proc. Acad. Nat. Sci. Phila. vol. xi. (1859), p. 133; vol. 

 xiii. (1861) p. 116. 



LEPTOSCOPUS Gill. 

 Leptoscopus Gill, loc. cit. 



Leptoscopus macropygus Gill. 

 Uranoscopus macropygus Rich. 



CRAPTALUS Giinther. 

 Craptalus Giinther, Annals and Mag. Nat. Hist. ser. iii. vol. vii. p. 86, (1861.) 



[Oct. 



